Caliper piston surface rust

So my front brake piston looks like its seen better days..



Think that will clean up or does it need to be replaced??

 

i'd say that's a little more than surface rust. the problem is the chrome around the rust will start flaking and tear the seals right up

 

I've been polishing on it a bit and its actually coming clean.. Should the cylinder be able to rotate freely? I'm trying to get the back side of the cylinder to clean but it doesn't seem to be rotating.

 

is the piston out of the caliper? you need to get the piston out then just spray some paint inside the the piston cavity, that's the least of your problems

 

The inside I could care less about. The outside surface is what I'm concerned about. Its still in the caliper. I polished the outside of it as best I could. The reason I'm concerned is the brakes are not retracting. I've cleaned the office in the master cylinder. The mc seems to be working fine.. Going to purge brake tomorrow and try to get some new fluid in the lines.

 

That Caliper Piston looks real bad

You need a flawless surface within the Pistons "Travel-area".

Don't risk it.
Replace it.

 

Agree..replace that piston.......disconnect brake line at caliper.....you can pop out the piston out by blowing compressed air in thru the brake line at the caliper .....watch your fingers....you may want to put a small piece of wood between the piston to absorb blow when the piston pops out.......that piston is shot.....hopefully the caliper bore will clean up.....replace seals....

Maybe that piston will clean up on a bench grinder/polisher......if not...definitely replace piston......


REMEMBER: Safety first at all cost......

 

Yeah hold on here.

For starters, TAKE IT APART.

The piston needs to come out, and the seals get replaced. You will find that there is crud built up in the channels where the seals go, behind the seals, which is why the piston is binding.

You can clean that piston up with Scotchbrite and see how it looks. What you're looking for is pitting in the area swept by the seals. Look at the piston in the pic below. That pitting is beyond the area swept by the seals, so it was re-usable.

THEN YOU NEED TO CLEAN THE CHANNELS IN THE CALIPER where the seals go. Dentally, surgically clean. See second pic below. Then you install NEW SEALS.

What you've been doing won't solve anything. You need to rebuild the caliper. Len has new pin boots too if yours are toast.

SERVICEABLE EVEN THOUGH PITTED PISTON:




CALIPER SEAL CHANNELS gotta be CLEAN:

 

Nice save!

When you get ready to reassemble the Caliper lube everything with fresh, clean Brake Fluid.

 

If no access to compressed air how would you recommend getting the piston out? I also don't have a grease gun! My truck doesn't have grease nipples.

 

THIS IS DANGEROUS!!! I am not actually advising that you do this. Polock has a hole in his ceiling from this.

put about 1/2 oz of water in the piston. put a regular bolt in the banjo bolt hole, and close the bleeder screw. heat the back of the caliper. The heat will soften the seals. The water will turn in to steam.... then the piston will SHOOT out with force.

REMEMBER THIS IS DANGEROUS, AND FOR LEGAL REASONS, I AM NOT ACTUALLY ADVISING YOU DO THIS

 

Before you disconnect the brake line use hydraulic pressure to pop it out. Messy but effective.

If the caliper is already disconnected take it to your local garage or fix-it shop (NOT a dealer) and see if they'll use their grease gun to force it out for you.

Or invest in a basic grease gun for $20 or so.

 

Mill, I'm NOT doing that Fitz, good idea, I'll put a bucket under the caliper and just use hydraulic pressure to pop it out

That is next month's project.

 

hey... it works!

 

if its pushed out far enough, wrap a cloth around the piston and pull it out with channel locks, not the best answer, but i have done it before when i had lack of tools. hooking it back up to the hydraulic line and pumping it till the hydraulics push it out is better, like bigfitz52 said, but make sure ur outside because you will throw fluid

 

FYI.... if you use this method, be sure you grip an area of the caliper piston that does not retract into the caliper, or you WILL end up having to source a new caliper pistion.

 

this guy said it worked great

 

My pistons were not frozen as his seems to be......compressed air work great for popping mine out.......however I am not suggesting that he does this....otherwise if his does pop out...it will probably come out with such great force......it would be DANGEROUS.......

Forget the suggestion using an air compressor......

SAFETY FIRST AT ALL COST.

 

Lol I don't have an air compressor to use! I think I'll go with the Fitz method In a bucket of course!

 

Polock - is that a picture of you????

 

yea, that was last Saturday night when i took a bath to go into town. i got me a cork to go in that hole but sometimes it pops out when i sneeze

 

is that hole from your caliper piston removal "incident"?

 

ha ha ha no no, i used to be a gunsmith